The invention relates generally to a method and apparatus for transmitting digital information over a network. More specifically, the invention relates to a method and apparatus for protecting such transmitted information from unauthorized replication, publication, and distribution.
The Internet is an international collection of interconnected networks currently providing connectivity among millions of computer systems. One popular form of network communication among Internet users is electronic mail (e-mail). E-mail is a xe2x80x9cstore and forwardxe2x80x9d service that enables sending computer systems to electronically exchange text messages and computer files with receiving computer systems across the globe. The text messages pass over the Internet from computer system to computer system to arrive at their destination. Often computer files accompany the text messages on the journey as attachments.
Attachments when opened can produce a variety of outputs. For example, an output can be the display of a formatted document, execution of a software program, the playing of music or other sounds, or the display of static and animated graphical images. Many e-mail systems, however, typically limit the size of e-mail messages, and attachments are either smaller than this limit or are broken into smaller files and reconstructed by the receiver. Consequently, electronic document delivery systems have emerged as another popular store-and-forward service, to handle the delivery of large files across the network.
Another increasingly popular avenue for exchanging information among computer systems is the World Wide Web (xe2x80x9cWebxe2x80x9d). The Web is a part of the Internet that provides a graphics and sound-oriented technology used by computer systems to access a vast variety of digital information, e.g., files, documents, images, and sounds, stored on other computer systems, called xe2x80x9cWeb sites.xe2x80x9d A Web site consists of electronic pages or documents called xe2x80x9cWeb pages.xe2x80x9d Often a Web page has links, called hyperlinks, to files and documents at other Web pages on the Web.
Computer system users can obtain digital information from these Web sites through a graphical user interface produced by executing client software called a xe2x80x9cbrowser.xe2x80x9d Examples of commercially available Web browsers include Netscape Navigator(trademark) and Microsoft Internet Explorer(trademark). Web browsers use a variety of standardized methods (i.e., protocols) for addressing and communicating with Web sites. A common protocol for publishing and viewing linked text documents is HyperText Transfer Protocol (HTTP).
To access a Web page at a Web site, a computer system user enters the address of the Web page, called an Uniform Resource Locator (URL), in an address box provided by the Web browser. The URL can specify the location of a Web server or a file on a Web server. Accessing the Web page downloads the contents of that Web page to the requesting computer system. The result of such downloading can be an wide variety of outputs at the computer system, including any combination of text, graphics, audio, and video information (e.g., images, motion pictures, animation, etc.). Accessing the Web page can also invoke execution of an application program.
A consequence of transmitting information using these above-described techniques, however, is that the sender of the information can lose control of that information after e-mailing the information to the receiving system or making a Web page publicly available on the Internet. Control of the information passes to the receiver, and any hope held by the sender to keep the information from further dissemination rests on the receiver. Most often, however, any such hope is misplaced, particularly on the Internet, where the receivers of the information can be numerous and anonymous. Thus, there is a need for a method and apparatus by which a sender can limit the unauthorized replication, publication, and distribution by a receiver of transmitted information.
The invention features a method for providing protection from unauthorized use of messages by a system. In one aspect, the method includes receiving at the system digital information representing a message. The digital information is stored in a storage device in a manner designed to conceal the message from unauthorized access. The digital information is accessed, the message is generated from the digital information for output at the system, and use of the generated message is restricted. In one embodiment, use of the generated message is limited to outputting the generated message at the system and printing a copy of the generated message. In another embodiment, use of the generated message is limited to outputting the generated message at the system.
In another aspect, the invention features a computer system for providing protection from unauthorized use of digital information received over a network. The system includes a storage device and a processor storing the digital information in the storage device in a manner designed to conceal the message from unauthorized access. A message generator accesses the digital information stored in the storage device to generate the message from the stored digital information for output at the system. However, the message generator restricts use of the generated message. In one embodiment, the computer system includes an output device, and the message generator limits use of the generated message to outputting the generated message at the output device. In another embodiment, the message generator limits the use to outputting the generated message at the output device and at a printing device.
Concealing the message from unauthorized access can be achieved by encoding the digital information before the processor stores the digital information in the storage device, storing the digital information at randomly determined address locations of the storage device, or by other techniques known to one skilled in the art.
The computer system can also include a process monitor for monitoring the computer system for process changes that occur on the computer system while the message is being output at the output device. The process monitor terminates the outputting of the message at the system upon detecting a process change.